1. Field of the Invention
This invention relates in general to semiconductor devices and specifically to non volatile memory devices.
2. Description of the Related Art
Non volatile memory devices utilize charge storage structures for selectively storing charge indicative of a bit of information to be stored. Such charge storage structures may include nitride, silicon nanocrystals, semiconductor material, or conductive material e.g. metals.
Some memories utilize multi-bit (multiple bit) memory cells. A multi-bit memory cell is a cell that can store more than one bit of information. Some multi-bit cells include a charge storage structure that has multiple charge storage locations or regions in the charge storage structure. Charge is selectively added to each region to selectively store a bit in the cell.
One problem with some multi-bit cells with a charge storage structure having multiple charge storage locations is that the charge may migrate between the charge storage locations, especially with a higher conductivity of some charge storage structure material.
What is desirable is a multi-bit memory cell configuration having separate charge storage structures.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The features shown in the Figures are not necessarily drawn to scale.